Manage DNS for Your Instances

Once your instances can reach internal platform services, they can resolve a DNS zone that you own and that I/O Cloud keeps in sync with your own instances' IP addresses, alongside normal internet DNS through the same resolver. See DNS for how the pieces fit together.

Prerequisites

• Connected to internal platform services — this guide depends on the router and host route set up there.
• The OpenStack CLI installed and configured.

Steps

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Checklist: None

Create your DNS zone

Any project member can create a zone — no special role needed. Zone names are shared across all tenants and handed out first-come-first-served, so pick a label that's recognizably yours.

openstack zone create --email you@yourdomain.tld \
  <your-zone-label>.instances.compute.eu-c1-tst.stud-io.cloud.

Point your network at your zone

1. Tell your network which zone to publish instance records into:

   openstack network set --dns-domain \
     <your-zone-label>.instances.compute.eu-c1-tst.stud-io.cloud. <your-net>

2. Turn on publishing for the subnet:

   openstack subnet set --dns-publish-fixed-ip true <your-subnet>

Instances created from this point on get an A record automatically — nothing further to do per instance.

Use the resolver

Point your subnet's DNS at the internal resolver, which serves your zone and recurses normally for everything else.

openstack subnet set --dns-nameserver 10.0.245.2 <your-subnet>

This depends on the host route set up in Connect to Internal Platform Services — without it, the resolver is unreachable and instances won't get DNS at all.

Troubleshooting

• A record missing for an instance created before you completed these steps: existing instances don't retroactively publish. Nudge it once:

  openstack port unset --dns-name <port>
  openstack port set --dns-name <hostname> <port>

  Instances created after step 2 above don't need this — they publish automatically.
• dig from the instance times out: check the host route from Connect to Internal Platform Services is present and the instance has renewed its DHCP lease since it was added.
• Zone name already taken: names aren't reserved per project — pick a different label.